"Dickes B - Kletterführer Berlin-Brandenburg", 2. Auflage 2013, Gerald Krug, Geoquest Verlag Halle, ISBN 978-3-00-016977-9
Despite the complete absence of natural rock formations, Berlin still offers some remedies for the vertically-addicted: artificial climbing walls, gyms, chiselled bunkers and semi-legal buildering. With more than 100 places to climb, you should be able to get pumped.
A nice overview of all locations can be found at http://www.klettern-in-berlin.de (in German).
An excellent guidebook is "Dickes B": http://www.geoquest-verlag.de/?q=node/77
Did you know that you can create an account to record, track and share your climbing ascents? Thousands of climbers are already doing this.